Engineers 'Hone' In on Solution for Tiny V-8 Engine

It's one thing to build a scale model of a car. It's another to power it with a working quarter-scale V-8 engine. That is exactly what the engineer Gary Conley did at the recent International Manufacturing Technology Show (IMTS) in Chicago. He showed off the supercharged Stinger 609, which is said to be the smallest four-cycle production V-8 in the world.

The engine might never have made it to the IMTS without the outside manufacturing expertise of engineers from Sunnen Products Co., who worked with Conley to make the engine's cylinder liners. Using a Sunnen hone to produce the cross-hatchings inside the liners, along with a separate process to "plateau hone" them, Conley was able to provide adequate lubrication for the engine at speeds of more than 10,000rpm.

"The problem is that the molecular size of oil doesn't scale down," Conley told us. "We found that out when we ran the engine. You couldn't stay in the room with it, because there was too much smoke."

Conley worked with Sunnen to develop a two-step solution to the problem. First, the engineering team used a coarse stone on the honing machine to create cross-hatched "valleys" that allowed the inside walls of the liners to retain oil. Then, they used a finer stone to shave off the "peaks" of the cross-hatchings, enabling the piston rings to seat more efficiently.

"The smaller the displacement of the engine, the more critical it is to control the oil," Conley said. "That's why you need the cross-hatch -- it helps retain the oil."

Conley's Stinger 609 engine, which packed the aisles at the IMTS, is named for its 6.09-cubic-inch displacement. With a one-inch bore and a 0.952-inch stroke, the engine puts out 9.5HP and 13 pounds of supercharged boost at 10,000rpm. It is designed to provide power for scale-model cars.

Production runs of the Stinger 609 are small. Conley's company, Conley Precision Engines Inc., built 40 on the first run and is producing 70 on the second. Eventually, he hopes to scale up his runs to between 150 and 180 of the units, which cost between $5,600 and $7,500 each.

The production runs could have easily been zero without Sunnen's help. "We worked nine months, 12 hours a day to solve the oil problem before we finally talked to Sunnen," he said. "Without them, this engine would not be available right now."

mcj804: The engine puts out 9.5 bhp, not 13. The 13 lbs cited in the story is the amount of boost from the supercharger. The article doesn't give the weight of the engine, so we can't compute the engine's power to weight ratio. The correct way to evaluate the power output is to say that its specific output is 1.56 bhp/cu.in. This is pretty good. Two of the highest output American V8 engines are those in the 2013 Ford Shelby GT500 (1.86 bhp/cu.in.) and the 2013 Corvetter ZR1 (1.69 bhp/cu.in.). The V6 in the 2012 Honda Accord EX-L is rated at 1.28 bhp/cu.in.

I, too, am impressed. The challenges must have been incredible! It goes to show that things aren't always to simple as they might first appear. Just like when they were scaling down IC manufacturing, the smaller lines created all sorts of optical and delivery problems.

Too bad I didn't get to see it. I am always impressed by someone who does a really good job! Kudos to you and your team!

It is quite an accomplishment and praiseworthy indeed. However, developing 13hp is a far cry more down-sized than the 1/4 size scale of the engine. One would expect a great deal more than 130hp from a full-sized super-charged V8. It appears that the power-to weight ratio doesn't scale very well.

Kudos for overcoming the difficulties and achieving this amazing engine.

I have to agree with the general tone of most responses that this is an amazing engineering achievement. A supercharged V-8 is already loaded with engineering innovation. To shrink that down to 1/4 size, I'm sure Mr. Conley had to solve more problems than just this oil retention issue. With national mandates to improve passenger car mpg, this development may not seem quite so out of the mainstream a few years from now.

Industrial workplaces are governed by OSHA rules, but this isn’t to say that rules are always followed. While injuries happen on production floors for a variety of reasons, of the top 10 OSHA rules that are most often ignored in industrial settings, two directly involve machine design: lockout/tagout procedures (LO/TO) and machine guarding.

Focus on Fundamentals consists of 45-minute on-line classes that cover a host of technologies. You learn without leaving the comfort of your desk. All classes are taught by subject-matter experts and all are archived. So if you can't attend live, attend at your convenience.